Amino-functional polysiloxanes are widely used in the textile industry as fibre lubricants and as fabric softeners and anti-wrinkle agents, and are also used in the personal care industry as hair conditioners and in skin care compositions. Mercapato-functional polysiloxanes are also known, and have been used in similar applications as amino-functional polysiloxanes. Organopolysiloxanes containing both amino functional and mercapto functional groups in the same polymer have recently been described in WO 2006/122018.
One of the major disadvantages of topical finishes prepared with fluorocarbon polymers is that they impart a harsh feel to the fabric surface. There is a need for textile treatment agents which impart oleophobicity and oil repellency to fabrics without imparting a harsh feel to the fabric surface, and preferably whilst at the same time imparting an improvement in feel compared to untreated fabric. Organopolysiloxanes containing both an amino and mercapto functional group are useful to prepare fluorosilicones for the treatment of fabrics, as described in WO 2006/121171. The resulting treatment renders textiles oleophobic, but yet have improved hand or feel compared to other fluoro treatments.
As amino-mercapto functional organopolysiloxane are becoming more useful as textile treatments, new industrial processes for their preparation are needed. In particular, processes are needed to enhance quality and consistency of the resulting product.
The present inventors have discovered a new method for preparing amino-mercapto functional organopolysiloxanes that provides such enhancements.